How UL 62368-1 Replaced Legacy IT and AV Safety Rules

This article explains how the hazard-based UL 62368-1 safety standard replaced legacy prescriptive rules for audio, video, and information technology equipment. You will learn why the electronics industry transitioned away from the older UL 60950-1 and UL 60065 standards, how Hazard-Based Safety Engineering (HBSE) works, and the specific ways this new framework classifies energy sources and safeguards to foster modern hardware innovation.

The Problem with Legacy Prescriptive Standards

For decades, electronic products were governed by two separate standards: UL 60950-1 for information technology equipment (ITE) and UL 60065 for audio and video (AV) equipment. These legacy frameworks were prescriptive. They consisted of rigid checklists dictated by historical accidents. Manufacturers had to follow exact construction rules, regardless of whether a new technology actually posed a threat.

As technology evolved, the line between IT and AV equipment blurred. Devices like smartphones, smart TVs, and laptops combined computing and media capabilities, forcing manufacturers to navigate two different, overlapping sets of rules. Furthermore, because prescriptive standards only addressed known technologies, any new component—such as a novel battery chemistry or a compact power supply—required tedious amendments to the standards before a product could be certified.

The Shift to Hazard-Based Safety Engineering (HBSE)

To solve the convergence and innovation problem, the International Electrotechnical Commission (IEC) and Underwriters Laboratories (UL) introduced 62368-1. This single standard merged the scopes of both 60950-1 and 60065. More importantly, it abandoned prescriptive rules in favor of Hazard-Based Safety Engineering (HBSE).

Instead of waiting for a device to cause harm and then writing a rule against that specific design, HBSE focuses on the underlying science of how injury occurs. It requires engineers to identify potential hazards early in the design phase and implement appropriate protections based on the severity of the energy present, rather than the type of product being built.

The Three-Block Model of UL 62368-1

UL 62368-1 evaluates product safety using a straightforward three-block model:

  1. Energy Source: The standard identifies all potential hazards within a device, including electrical, thermal, kinetic (mechanical), chemical, and radiation energy.
  2. Transfer Mechanism: It looks at how that energy could potentially reach a human body or surrounding materials.
  3. Body Part or Material: It evaluates the vulnerability of the user or the environment to that specific energy transfer.

To prevent injury or fire, the standard requires manufacturers to place a Safeguard between the energy source and the user to block or weaken the transfer mechanism.

Classification of Energy Sources and Users

Under UL 62368-1, energy hazards are categorized into three straightforward tiers based on their potential to cause harm:

  • Class 1: Energy levels are low enough that they are not painful and will not cause ignition. No safeguards are required.
  • Class 2: Energy levels are painful to touch and may cause ignition, but they will not cause a severe injury. At least one basic safeguard is required.
  • Class 3: Energy levels are capable of causing severe injury, death, or rapid fire spread. Double or reinforced safeguards are mandatory.

The standard also categorizes the people interacting with the equipment into three groups: Ordinary Persons (everyday consumers), Instructed Persons (those trained to avoid specific hazards), and Skilled Persons (technicians with deep knowledge of the equipment). A device with a Class 3 energy source requires reinforced physical barriers if an Ordinary Person is using it, whereas a warning label might suffice inside an area accessible only to a Skilled Person.

How This Impacts Modern Electronics Design

By shifting to UL 62368-1, the electronics industry moved from a culture of rule-following to a culture of performance-based risk management. Hardware engineers now have the freedom to use new materials, shrink product footprints, and invent entirely new product categories. As long as the manufacturer can prove through testing that their chosen safeguards effectively stop Class 2 and Class 3 energy sources from reaching the user, the product will pass certification. This makes UL 62368-1 future-proof, ensuring safety standards no longer bottleneck technological advancement.